Next-generation analysis of synovial tissue architecture

Key advances Single-cell analysis identified a subset of polyfunctional T cells in synovial tissue from patients with psoriatic arthritis that produce several pro-inflammatory cytokines and are associated with disease activity2. Distinct fibroblast subtypes with non-overlapping pathogenic roles identified by single-cell analysis in rheumatoid arthritis (RA) synovial tissues indicate that selective targeting of such cells could represent a novel therapeutic strategy3. Synovial pathotype classification and RNA sequence analysis in early arthritis can predict the development of persistent, erosive RA that will require treatment with biologic DMARDs4. The synovium is the main target tissue of inflammatory arthritides such as rheumatoid arthritis and psoriatic arthritis. In 2019, new technologies for examining the molecular characteristics of specific cell subsets have enabled advances in our understanding of the architecture of synovial lymphoid aggregates, macrophage infiltrates and synovial fibroblast subsets.